The present invention relates to a valve inspection chamber
There is a massive infrastructure network of underground piping in every major city to carry liquids, such as drinking water or sewage. Valves of various types are placed strategically along the network, to prevent unwanted backflows in the network and enable portions of the piping to be isolated during servicing. When valves are buried more than two feet below the surface of the ground, manholes are generally required in order to provide access to the valves for inspection or servicing.
U.S. Pat. Nos. 5,826,609; 6,029,684; 6,125,878 (Watts) considered together describe a system that enables valves to be inspected and serviced without the use of the manhole. This is accomplished through a methodology described and claimed in U.S. Pat. No. 5,826,609, in which a retrieval tool described and claimed in U.S. Pat. No. 6,125,878 is used to recover for inspection and replacement a valve member from a valve inspection chamber described in U.S. Pat. No. 6,029,684.
The present invention relates to an alternative configuration of valve inspection chamber.
According to the present invention there is provided a valve inspection chamber which includes a housing having a first horizontal flow opening, a second horizontal flow opening, and a vertical inspection and valve retrieval opening. A valve cassette is provided which includes a frame and a valve member movable relative to the frame between an open position and a closed position. A valve cassette receptacle is positioned in the housing in a flow path of one of the first horizontal flow opening and the second horizontal flow opening and aligned with the vertical inspection and valve retrieval opening, such that the valve cassette can be inserted and retrieved through the vertical inspection and retrieval opening. Means is provided for maintaining the valve cassette in engagement with the valve cassette receptacle until a preset vertical force is exerted. Means for engaging a retrieval tool is positioned on either the frame or the valve member of the valve cassette.
With the Watts system, hinge pins for the flapper valve member were snapped into clips in the housing. With the valve inspection chamber, as described above, a valve cassette is slid into a valve cassette receptacle within the housing. This provides a number of advantages. It can be adapted to a variety of valve types, such as gate valves; whereas the Watts system could only be used with flapper valves. More importantly, it simplifies the installation procedure and the tool that is used for installation and make possible further refinements, as will hereinafter be further described.